1. State Key Laboratory of Bio-Organic & Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Ling Ling Road, Shanghai 200032, P. R. China
2. AstaTech BioPharmaceutical Corporation, 488 Kelin West Road, Wengjiang, Chengdu, Sichuan 611130, P. R. China